git.zerfleddert.de Git - rsbs2/blob - rsb-lz.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <strings.h>
   4 #include <string.h>
   5 #include <unistd.h>
   6 #include <errno.h>
   7 #include "rsb-crc.h"
   8 #include "rsb-lz.h"
   9 #include "filesystem.h"
  10
  11 void err_exit(const char *fname)
  12 {
  13         fprintf(stderr,"%s: error extracting...\n", fname);
  14         exit(1);
  15 }
  16
  17 struct data_in_s {
  18         unsigned char *start;
  19         unsigned char *stop;
  20         unsigned char bitpos;
  21         unsigned char byte;
  22 };
  23
  24 struct data_out_s {
  25         unsigned char *pos;
  26         unsigned char *end;
  27 };
  28
  29 unsigned char get_next_in_byte(struct data_in_s *data_in)
  30 {
  31         unsigned char byte;
  32
  33         if (data_in->stop < data_in->start)
  34                 err_exit(__func__);
  35
  36         byte = *(data_in->start);
  37         data_in->start++;
  38
  39         return byte;
  40 }
  41
  42 unsigned char get_next_bit(struct data_in_s *data_in)
  43 {
  44         unsigned char bitval;
  45
  46         if (data_in->bitpos == 0x80) {
  47                 data_in->byte = get_next_in_byte(data_in);
  48         }
  49
  50         bitval = data_in->bitpos & data_in->byte;
  51
  52         data_in->bitpos >>= 1;
  53         if (data_in->bitpos == 0) {
  54                 data_in->bitpos = 0x80;
  55         }
  56
  57         if (bitval == 0)
  58                 return 0;
  59
  60         return 1;
  61 }
  62
  63 unsigned int get_next_bits(struct data_in_s *data_in, unsigned int bits)
  64 {
  65         unsigned int bit;
  66         unsigned int next_bits;
  67
  68         bit = 1 << (bits - 1);
  69
  70         next_bits = 0;
  71         while (bit != 0) {
  72                 if (data_in->bitpos == 0x80) {
  73                         data_in->byte = get_next_in_byte(data_in);
  74                 }
  75
  76                 if ((data_in->bitpos & data_in->byte) != 0)
  77                         next_bits = next_bits | bit;
  78
  79                 bit = bit >> 1;
  80
  81                 data_in->bitpos >>= 1;
  82
  83                 if(data_in->bitpos == 0) {
  84                         data_in->bitpos = 0x80;
  85                 }
  86         }
  87
  88         return next_bits;
  89 }
  90
  91 void write_byte(unsigned char byte, struct data_out_s *data_out)
  92 {
  93         if (data_out->pos > data_out->end) {
  94                 err_exit(__func__);
  95         }
  96
  97         *(data_out->pos) = byte;
  98         data_out->pos++;
  99 }
 100
 101 void lz_expand(struct data_in_s *data_in, struct data_out_s *data_out)
 102 {
 103         unsigned int pos;
 104         unsigned int wordoffset;
 105         unsigned int i;
 106         unsigned char byte;
 107         unsigned int wordlen;
 108         unsigned char buf[1024];
 109
 110         pos = 1;
 111
 112         while (1) {
 113                 while (1) {
 114                         /* Compressed/uncompressed? */
 115                         if (get_next_bit(data_in) == 0)
 116                                 break;
 117
 118                         /* Uncompressed byte */
 119                         byte = get_next_bits(data_in, 8);
 120
 121                         write_byte(byte, data_out);
 122
 123                         /* Save byte in buffer, to be reused later */
 124                         buf[pos] = byte;
 125                         pos = (pos + 1) & 0x3ff;
 126                 }
 127
 128                 /* offset for start of dictionary word */
 129                 wordoffset = get_next_bits(data_in, 0x0a);
 130                 if(wordoffset == 0)
 131                         return;
 132
 133                 /* length of dictionary word used */
 134                 wordlen = get_next_bits(data_in, 0x04) + 1;
 135                 for (i = 0; i <= wordlen ; i++) {
 136                         /* lookup dictionary byte */
 137                         byte = buf[(wordoffset + i) & 0x3ff];
 138                         write_byte(byte, data_out);
 139                         /* Save byte in buffer, to be reused later */
 140                         buf[pos] = byte;
 141                         pos = (pos + 1) & 0x3ff;
 142                 }
 143         }
 144 }
 145
 146 /* Checksum is only used for the compressed firmware in 'firmware' */
 147 unsigned int crc_check(unsigned char *buf, unsigned int len, unsigned int magic)
 148 {
 149         unsigned int file_crc;
 150         unsigned int my_len;
 151         unsigned int crc;
 152         unsigned int my_magic;
 153
 154         my_len = *((unsigned int*)(buf + 0x20));
 155         my_magic = *((unsigned int*)(buf + 0x24));
 156
 157         if (my_magic != magic) {
 158                 printf("\nmagic: 0x%08x <-> 0x%08x\n", my_magic, magic);
 159                 return 2;
 160         }
 161
 162         if (len < my_len)
 163                 return 3;
 164
 165         crc = ~rsb_crc(~0x00, buf, len);
 166         file_crc = *((unsigned int*)(buf + len));
 167
 168         if (file_crc != crc) {
 169                 printf("\nChecksums: 0x%08x <-> 0x%08x!\n", crc, file_crc);
 170                 return 4;
 171         }
 172
 173         return 0;
 174 }
 175
 176 void extract_lz_file(unsigned char *inbuf, unsigned char *name, unsigned char check_crc)
 177 {
 178         unsigned int len;
 179         unsigned char *outbuf;
 180         struct data_in_s data_in;
 181         struct data_out_s data_out;
 182
 183         if (*((unsigned int*)inbuf) != LZ_MAGIC)
 184                 err_exit(__func__);
 185
 186         len = *((unsigned int*)(inbuf + 4));
 187         printf(", length: %d", len);
 188
 189         if ((outbuf = malloc(len)) == NULL) {
 190                 perror("malloc");
 191                 exit(1);
 192         }
 193
 194         bzero(outbuf, len);
 195
 196         data_in.start = inbuf + 8;
 197         data_in.stop = inbuf + len;
 198         data_in.byte = 0x00;
 199         data_in.bitpos = 0x80;
 200
 201         data_out.pos = outbuf;
 202         data_out.end = outbuf + len;
 203
 204         lz_expand(&data_in, &data_out);
 205
 206         if (check_crc) {
 207                 unsigned int crclen;
 208                 int ret;
 209
 210                 crclen = *((unsigned int*)(outbuf + 0x20));
 211
 212                 if ((ret = crc_check(outbuf, crclen, 0x46335053)) != 0) {
 213                         printf("crc_check return: %d\n", ret);
 214                         err_exit(__func__);
 215                 }
 216         }
 217
 218         write_file((char*)name, outbuf, len);
 219
 220         free(outbuf);
 221 }